在文件中创建一个txt文件后，就可以使用程序了
本程序从正文文件text.txt中读入一篇英文短文，统计该短文中不同单词及出现次数，并按词典编辑顺序将单词及出现次数输出到正文文件word.txt中。
程序用一棵有序二叉树存储这些单词及其出现的次数，边读入边建立，然后中序遍历该二叉树，将遍历经过的二叉树上的结点的内容输出。
#include "stdafx.h"
# include <stdio.h>
# include <malloc.h>
# include <ctype.h>
# include <string.h>
# define INF "text.txt"
# define OUTF "word.txt"
typedef struct treenode {
char *word;
int count;
struct treenode *left, *right;
} BNODE;
int getword(FILE *fpt, char *word)
{ char c;
c=fgetc(fpt);
if ( c == EOF)
return 0;
while(!(tolower(c) >= 'a' && tolower(c) <= 'z'))
{ c=fgetc(fpt);
if ( c == EOF)
return 0;
} /* 跳过单词间的所有非字母字符 */
while(tolower(c) >= 'a' && tolower(c) <= 'z')
{ *word++ = c;
c = fgetc(fpt);
}
*word = ' ';
return 1;
}
void binary_tree(BNODE **t, char *word)
{ BNODE *ptr, *p; int compres;
p = NULL;
ptr=*t;
while (ptr) /* 寻找插入位置 */
{ compres=strcmp(word,ptr->word); /* 保存当前比较结果 */
if (!compres)
{ ptr->count++ ;
return; }
else
{ p=ptr ;
ptr = compres>0 ? ptr->right : ptr->left;
}
}
ptr = (BNODE *)malloc(sizeof(BNODE));
ptr->left = ptr->right = NULL;
ptr->word = (char *)malloc(strlen(word)+1);
strcpy(ptr->word, word);
ptr->count = 1;
if (p == NULL)
*t=ptr ;
else if (compres > 0)
p->right = ptr;
else
p->left = ptr;
}
void midorder(FILE *fpt, BNODE *t)
{ if ( t == NULL )
return;
midorder(fpt, t->left);
fprintf(fpt, "%s %d
", t->word, t->count);
midorder(fpt, t->right);
}
void main()
{ FILE *fpt; char word[40];
BNODE *root=NULL;
if ((fpt=fopen(INF, "r")) == NULL)
{ printf("Can't open file %s
", INF);
return;
}
while(getword(fpt, word) == 1)
binary_tree( &root, word );
fclose(fpt);
fpt = fopen(OUTF, "w");
if (fpt == NULL)
{ printf("Can't open file %s
", OUTF);
return;
}
midorder(fpt, root);
fclose(fpt);
}